Plastic housing

ABSTRACT

A plastic housing for an electric or electronic circuit to be disposed in an electrical or electronic appliance. The plastic housing is configured such that the circuit is held in the housing in a fire-resistant fashion. The housing contains at least two housing elements which are releasably connected together. The housing has a first housing element formed of a fire-resistant plastic material and a second housing element formed of a non-fire-resistant plastic material. The second housing element of non-fire-resistant plastic material has at least one flap connected by a film hinge to the remaining part of the housing element. The electrical or electronic appliance is preferably a water-carrying domestic appliance, in particular a washing machine, a laundry drier or a washer-drier.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention concerns a plastic housing for holding an electric or electronic circuit in an appliance in a fire resistant manner.

In domestic appliances which carry water such as for example washing machines, electronic circuits such as for example the electronic frequency converter system, must be disposed in a housing in such a way that on the one hand they are protected from splash or spray water and on the other hand in the event of a fire in the domestic appliance they remain in their intended fixed position and cannot come loose or drop out, as in that case the casing of the domestic appliance could carry electrical voltage.

For that purpose the electronic frequency converter system of a washing machine is disposed in a housing which is entirely formed of a plastic material of a fire-resistant nature, that is to say of a fire-resistant plastic material. Such a structure suffers from the disadvantage that such a fire-resistant plastic material is complicated and expensive to produce and is limited in terms of processing thereof.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a plastic housing which overcomes the above-mentioned disadvantages of the prior art devices of this general type, which is simpler and less expensive to produce and which can be processed in a more flexible fashion.

With the foregoing and other objects in view there is provided, in accordance with the invention, a plastic housing for an electric or electronic circuit to be disposed in an electrical or electronic appliance. The plastic housing contains at least two housing elements releasably connected together and include a first housing element formed of a fire-resistant plastic material and a second housing element formed of a non-fire-resistant plastic material. The housing elements hold the electric or electronic circuit in a fire-resistant fashion.

A core concept of the invention provides that it is no longer the entire housing that is formed of the fire-resistant plastic material, but only that part of the housing which holds the electric or electronic circuit. For that purpose the housing contains at least two housing elements which are releasably connected to each other. The first housing element is made from a fire-resistant plastic material while the second housing element contains a conventional, non-fire-resistant plastic material.

The partial use of a conventional plastic material simplifies and reduces the cost of production of the housing. This configuration also affords a greater degree of variability and flexibility in terms of the configuration of the housing.

A suitable plastic material with fire-resistant properties is preferably PPE+S/B X or PC-ABS-FR while a suitable material for a conventional plastic material is preferably PPTV20.

In a development of the invention the second housing element which is formed of the non-fire-resistant plastic material has a flap which is connected by a film hinge to the remaining part of the housing element. When exclusively using a fire-resistant plastic material, such a film hinge could not be implemented at all or it could not be implemented at justifiable cost or with a justifiable degree of complication and expenditure.

The flap can protect one or more connecting sockets or plugs of the electric or electronic circuit. Such a flap which is formed on the second housing element by a film hinge can alternatively also be releasably connected to the first housing element in such a way that the second housing element can be pivoted open by way of the film hinge and thus the housing can be opened and also closed again.

The electric or electronic circuit is preferably fixed within the housing to the first housing element formed of the fire-resistant plastic material. In a preferred embodiment the fixing is effected by a fixing element containing a fire-resistant plastic material. In a particularly preferred configuration the fixing element used is a fixing frame formed of PA66GF35FR. The fixing element may in addition also have a guide device and a coding device for the connecting sockets or plugs of the electric or electronic circuit. In that respect the guide device is preferably of such a configuration that at the same time it has the coding device.

The housing is further configured so that the electric or electronic circuit is protected therein from splash or spray water.

The electric or electronic circuit is preferably formed by a power circuit, in particular by an electronic frequency converter configuration for a drive motor of a washing machine, a laundry drier or a washer-drier (washing machine-laundry drier combination).

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a plastic housing, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic, exploded perspective view from the side of a front of a plastic housing for an electronic frequency converter configuration for a washing machine according to the invention; and

FIG. 2 is an exploded, perspective view of the plastic housing of FIG. 1 from the side of the rear.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a plastic housing for a washing machine electronic frequency converter configuration. The housing contains two housing elements 1, 2. A first housing element 1 in the form of a rear portion is formed of a plastic material PPE+S/B X (of a fire-resistant nature), and a second housing element 2 in the form of a front portion is formed of a non-fire-resistant plastic material PPTV20.

Formed on an underside 3 of the rear portion 1 are four support feet 4, while formed at an underside thereof there are in turn fixing elements 5 of a cross-section in the form of an inverted T. With the fixing elements 5, the support feet 4 can engage through corresponding slots in a support or bottom panel of a washing machine or can engage behind the support or bottom panel, thereby providing for secure fixing of the plastic housing in the washing machine.

Formed on an inside of the rear portion 1 are various abutments 6 against which can be applied a non-illustrated circuit board carrying the electronic frequency converter configuration for the washing machine. A fixing frame formed of the fire-resistant plastic material PA66GF35FR (not shown in the figures) is then put on to the front side of the circuit board. The fixing frame is retained by undercut configurations of fixing hooks 7 formed on the rear portion 1 and by snap hooks 8 which are disposed in opposite relationship to the fixing hooks 7 and which are also shaped on the rear portion 1 so that this affords a stable mount for the circuit board carrying the electronic frequency converter configuration.

The circuit board with the electronic frequency converter configuration can also be fixed to the fixing frame by the snap hooks, screws or the like prior to insertion into the rear portion 1, and can then be fitted together with the fixing frame into the rear portion 1. In that case the fixing frame can be of such a configuration that it itself (and not the circuit board) bears against the abutments 6.

The rear portion 1 further has openings 9, 10 through which connecting sockets on the circuit board are accessible. The connecting sockets can be mounted directly on the circuit board. They can however also be formed by guide elements which are formed on the fixing frame and which at the same time also have a plug coding device, together with contact strips disposed on the circuit board.

The front portion 2 of the housing has a plurality of ventilation slots 11 through which cooling air can pass into the interior of the housing. Formed on one side of the front portion 2 by a film hinge 12 is a protective flap 13 which, in the assembled condition of the housing, can be pivoted in such a way that it can be latched in front of the openings 9 and 10 in order to prevent the ingress of splash or spray water through those openings 9 and 10 into the interior of the housing and in particular on to the electronic frequency converter system. In that respect, the configuration ensures that, even when the protective flap 13 is closed, a slot still remains open for the passage therethrough of cables connected to the connecting sockets disposed on the circuit board.

A fixing flap 15 is also formed on the upper end of the front portion 2 by way of a film hinge 14. In the assembled condition of the housing, the flap 15 can be pivoted around the top side of the rear portion 1, in which case snap hooks 16 formed on the top side of the rear portion 1 engage through openings 17 in the fixing flap 15 of the front portion 2 and snap into engagement there. By virtue of such a configuration and by non-illustrated support elements, the front portion 2 is fixed to the rear portion 1 by way of the fixing flap 15. A main body 18 of the front portion 2 can now be pivoted around the film hinge 14 between the fixing flap 15 and the main body 18 so that the housing can be opened and closed by pivoting the main body 18 of the front portion 2 open and shut.

When the housing is closed by pivoting the main body 18 of the front portion 2 shut, on the one hand holding tongues 19 which are formed laterally on the front portion 2 come into snapping engagement behind corresponding fixing hooks 20 (see FIG. 2) which are formed at the sides of the rear portion 1. On the other hand snap hooks 21 which are formed at the underside of the front portion engage through openings 22 which are provided in the upper region of the front support feet 4 of the rear portion 1 in order to come into hooking engagement with their undercut configurations behind the exits of the openings 22.

Besides the support feet 4, a screw dome 23 which is formed laterally on the rear portion 1 and which has a screw guide sleeve 24 serves for fixing the entire housing to the domestic appliance.

Formed on the opposite side on the front portion 2 is a holding arm 25 with pipe holding clamps 26 which serve as hose holders.

Even when the housing is closed, openings remain free in the upper region of the housing at the sides, the openings permitting cooling air to pass therethrough. Accordingly cooling air which has penetrated into the housing through the vent openings 11 in the front portion 2 and which has passed over the electronic frequency converter configuration or over cooling bodies thermally coupled to power members disposed thereon and which has been heated thereby can issue again at both sides of the housing beneath the film hinge 14 between the main body 18 and the fixing flap 15 of the front portion 2. By virtue of an inclined configuration for the upper closure part of the front portion 2, in that case a suction effect is additionally also produced. In that case, cooling air enters at the side of the housing which is lower and issues again at the side of the housing which is higher (at the hose holding arm 25) and in so doing increasingly sucks in cooling air through the lower cooling openings 11. The effect is further increased by an air baffle wall 27 provided at the inside of the front portion 2.

Disposed in the rear portion 1 or in a fixing extension 28 formed thereon are holes 29 into which cable holding ties or tie holders for cable holding ties or also clips can be snappingly fitted. In that way, together with a cable guide 30 which is also formed on the fixing extension 28, cables or cable harnesses which are disposed within the electrical or electronic appliance are firmly fixed to the housing, whereby it is possible to prevent the cables from being chafed through.

This application claims the priority, under 35 U.S.C. § 119, of German patent application No. 10 2004 003 018.9, filed Jan. 20, 2004 and German patent application No. 10 2004 009 356.3, filed Feb. 26, 2004; the entire disclosure of the prior application is herewith incorporated by reference. 

1. A plastic housing for an electric or electronic circuit to be disposed in an electrical or electronic appliance, the plastic housing comprising: at least two housing elements releasably connected together and including a first housing element formed of a fire-resistant plastic material and a second housing element formed of a non-fire-resistant plastic material, said housing elements holding the electric or electronic circuit in a fire-resistant fashion.
 2. The plastic housing according to claim 1, wherein: said fire-resistant plastic material is a plastic material with fire-resistant properties; and said non-fire-resistant plastic material is a plastic material without fire-resistant properties.
 3. The plastic housing according to claim 1, wherein said second housing element has at least one flap, a film hinge, and a remaining part, said flap connected by said film hinge to said remaining part.
 4. The plastic housing according to claim 3, wherein said flap protects at least one connecting socket or plug of the electric or electronic circuit.
 5. The plastic housing according to claim 3, wherein said flap is releasably connected to said first housing element and the plastic housing can be opened by pivoting open said second housing element by way of said film hinge.
 6. The plastic housing according to claim 1, wherein the electric or electronic circuit is fixed within the plastic housing to said first housing element.
 7. The plastic housing according to claim 6, further comprising a fixing element for fixing the electric or electronic circuit to said first housing element, said fixing element formed of said fire-resistant plastic material.
 8. The plastic housing according to claim 7, wherein said fixing element has a guide and a coding disposed in said guide for connecting sockets or plugs of the electric or electronic circuit.
 9. The plastic housing according to claim 1, wherein the electric or electronic circuit is protected from spray or splash water within the plastic housing.
 10. The plastic housing according to claim 1, wherein the electric or electronic circuit is a power circuit.
 11. The plastic housing according to claim 7, wherein said fixing element is a fixing frame.
 12. The plastic housing according to claim 7, wherein said fire-resistant plastic material is a plastic material with fire-resistant properties.
 13. The plastic housing according to claim 7, wherein said fire-resistant plastic material is PA66GF35FR.
 14. The plastic housing according to claim 10, wherein the power circuit is a frequency converter circuit for a drive motor of a washing machine, a laundry drier or a washer-drier.
 15. The plastic housing according to claim 2, wherein said fire-resistant plastic material is PPE+S/B X or PC-ABS-FR and said non-fire-resistant plastic material is PPTV20.
 16. The plastic housing according to claim 3, wherein: said flap includes a first flap protecting at least one connecting socket or plug of the electric or electronic circuit and a second flap releasably connected to said first housing element and having said film hinge; and the plastic housing can be opened by pivoting open said second housing element by way of said film hinge of said second flap.
 17. The plastic housing according to claim 1, wherein the electrical or electronic appliance is selected from the group consisting of a water-carrying domestic appliance, a washing machine, a laundry drier and a washer-drier. 